Djokovic dug deep to best Nadal 4-6, 6-3, 7-6 (7-4) in Miami, running his 2011 record to a perfect 24-0.
It was the Serb's fourth title in as many events this season.
He downed Andy Murray in the final of the Australia Open in January, racking up his second career Grand Slam win in the process, and then prevailed over Roger Federer for the Dubai crown in February.
Djokovic also knocked off Nadal for the title at Indian Wells in California last month before topping him again Sunday in Miami.
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